Method of using differential measurement in two or more channels to improve sensitivity

ABSTRACT

A method to calibrate measurements of a test analyte in a test sample including measuring at least one test-light level responsive to reactions of at least one reagent group and at least one reactive test analyte in the test sample and measuring at least one control-light level responsive to reactions of at least one reagent group and at least one control analyte in a control sample. Each control analyte is a known amount of at least one reactive test analyte. The method further includes determining a presence of the reactive test analyte in the test sample based on the measured test-light levels and control-light levels. The reagent group and the reactive test analyte react by attaching to each other.

BACKGROUND

Currently, assays are read by human eye or high cost imaging system andthe reading of assays are determined by individual human judgment orexpensive equipment. The purpose of reading these assays is to determinewhether a test sample of biological or chemical material being assayedincludes a particular analyte, or a derivative or constituent of theanalyte. The particular analyte, which is the subject of the assay, isreferred to as a test analyte. The test sample may include biologicalmaterial such as urine, saliva, blood plasma, or the like. The testsample may include chemical material such as rainwater, sludge, or thelike.

An assay is performed using a substrate having a sensitive regionpatterned on the surface of the substrate. Such substrates may includechannels that wick the test sample up and over the sensitive regionspatterned within the channels. In some case, the substrate is made ofsilicon or glass and has a smooth surface. If the substrate includeschannels, the channels are etched in the substrate and the sensateregion is patterned within the etched channels. In other cases, thesubstrate is made of paper. If the paper substrate includes channels,the channels are defined by the type and/or density of the paper or bythickness variations in the paper.

The sensitive region reacts to exposure of a test analyte. The sensitiveregion is indistinguishable from the substrate outside the sensitiveregion until the sensitive region is exposed to the test analyte. Thereaction can be a bonding of the material in the sensitive region withthe test analyte. The reaction is detected by an emission of light fromthe reacted region. In some cases, light is incident on the assay afterexposure to a test sample. If a reaction has occurred, some of theincident light is reflected from the bonded material. For example, goldatoms are attached to the test analyte and incident light is reflectedfrom the bound gold atoms. In other cases, if a reaction has occurred,the bonded material fluoresces upon exposure to the incident light.

A human observes the sensitive region to determine if there was asufficient change in the appearance of the sensitive region relative tothe rest of the substrate. When readings to determine an exposure of thesensitive region to of a test analyte are made by the human eye, thereadings may not be consistent and may be prone to error. When assaysare read by equipment, such as a charge-coupled device (CCD), thedetermination of an exposure of the sensitive region to of a testanalyte may be consistent and relatively error free. However, theequipment typically must be high resolution to make the accuratedetermination and such equipment is expensive.

In some instances, it is useful to determine the amount of analyte inthe test sample. For example, if a physician is treating a physicalcondition for a patient and the patient's blood is the test sample

A market demand exists for a simple, inexpensive system to determinewhether a test sample of biological or chemical material being assayedincludes a particular analyte, or a derivative or constituent of theanalyte. There is also a market demand for quantifying the amount ofincludes a particular analyte, or a derivative or constituent of theanalyte in an inexpensive system.

SUMMARY

The invention provides in a first aspect a method to calibratemeasurements of a test analyte in a test sample. The method includesmeasuring at least one test-light level responsive to reactions of atleast one reagent group and at least one reactive test analyte in thetest sample, measuring at least one control-light level responsive toreactions of at least one reagent group and at least one control analytein a control sample. Each control analyte is a known amount of at leastone reactive test analyte. The method further includes determining apresence of the reactive test analyte in the test sample based on themeasured test-light levels and control-light levels. The reagent groupand the reactive test analyte react by attaching to each other.

The invention provides in a second aspect a test strip to calibratemeasurements of one or more test analytes in a test sample. The teststrip includes at least two channels, each channel including reagentportions having associated reagent groups. Each channel receives eitherthe test sample or a selected control sample. The selected controlsample includes a known amount of at least one test analyte and the testsample includes either an unknown amount of at least one test analyte oran undetectable amount of the test analytes.

The invention provides in a third aspect a system to calibratemeasurements of one or more test analytes from a test sample. The systemincludes a photodetector array and a processor communicatively coupledto the photodetector array. The photodetector detects light correlatedto at least three reagent portions of a test strip and detects areference light from at least one blank portion of the test strip. Theprocessor determines reaction light levels correlated to the lightdetected from each of the reagent portions, determines a reference-lightlevel correlated to the blank portion, forms calibration curves forrespective reagent groups based on respective first reaction lightlevels and respective second reaction light levels and determines anamount of one or more test analytes in the test sample based onplacements of third reaction light levels on respective calibrationcurves.

The invention provides in a fourth aspect a system to calibratemeasurements of one or more test analytes in a test sample. The systemincludes means for measuring test-light levels from reactions of testanalytes with reagent groups, means for measuring control-light levelsfrom reactions of control analytes with reagent groups, means forforming calibration curves based on detected control-light levels, andmeans for determining amounts of the test analytes in the test samplefrom placements of the test-light levels on the calibration curves.

DRAWINGS

FIG. 1 is a block diagram of one embodiment of a test strip.

FIG. 2 is a block diagram of one embodiment of a system to calibratemeasurements of one or more test analytes from a test sample.

FIGS. 3A and 3B are side cross-sectional views of one embodiment of thecontrol channel during a calibration process before and after a bondingevent, respectively.

FIGS. 4A and 4B are side cross-sectional views of one embodiment of atest-sample channel during a calibration process before and after abonding event, respectively.

FIG. 5 is a block diagram of one embodiment of a system to calibratemeasurements of one or more test analytes from a test sample.

FIG. 6 is a block diagram of one embodiment of a photodetector array.

FIG. 7 is a block diagram of one embodiment of a test strip.

FIG. 8 is a flow diagram of one embodiment of a method to determine apresence of a reactive test analyte in a test sample.

FIG. 9 is a block diagram of one embodiment of a test strip.

FIG. 10 is a flow diagram of one embodiment of a method to determine anamount of a reactive test analyte in a test sample.

FIG. 11 a cross-sectional side view of one embodiment of a system tocalibrate measurements of one or more test analytes from a test sample.

FIGS. 12A-12C are cross-sectional front views of one embodiment of asystem to calibrate measurements of one or more test analytes from atest sample at different times during a calibration process.

In accordance with common practice, the various described features arenot drawn to scale but are drawn to emphasize features relevant to thepresent invention. Reference characters denote like elements throughoutfigures and text.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings that form a part hereof, and in which is shown byway of illustration specific illustrative embodiments in which theinvention may be practiced. These embodiments are described insufficient detail to enable those skilled in the art to practice theinvention, and it is to be understood that other embodiments may beutilized and that logical, mechanical and electrical changes may be madewithout departing from the scope of the present invention. The followingdetailed description is, therefore, not to be taken in a limiting sense.

FIG. 1 is a block diagram of one embodiment of a test strip 32. The teststrip 32 is used to calibrate measurements of one or more test analytesin a test sample 40. The test strip 32 is used in conjunction with acalibration system 10 or 11 as described below with reference to FIGS. 2and 5. The test sample 40 is delivered from a well 55 of the sample tray27 to a first channel 70 of the test strip 32. The test sample 40includes a test analyte shown as a triangle and represented generally by47. The test analyte 47 is also referred to here as “first test analyte47.” In one implementation of this embodiment, the test sample 40 isintroduced to the first channel 70 through a hole in the test strip 32that is located over the test-sample channel 70. In an implementation ofthis case, the test sample 40 is pipetted into the hole.

The test strip 32 comprises three channels: the first channel 70, asecond channel 72, and a third channel 74. Each of the first channel 70,the second channel 72, and the third channel 74 comprise reagentportions 100 and reagent portions 110. The reagent portion 100 includesone type of reagent group and the reagent portion 110 includes anothertype of reagent group. The terms “reagent group” and “reagent” are usedinterchangeable throughout this document. As shown in FIG. 1, the row105 is a row of reagent portions 100 and the row 106 is a row of reagentportions 110.

A test analyte 47 is reactive to a reagent if the test analyte 47 andthe reagent attach or bond to each other when they contact each other.Such a bonding between the test analyte 47 and the reagent is referredto here as a bonding event. The contact required to initiate a bondingevent occurs when the test analyte 47 flows through the first channel 70past or through the reagent portion 100 and/or reagent portion 110. Ifthe test analyte 47 and the reagent group attach or bond to each other,the test analyte 47 is a reactive test analyte 47 to the respectivereagent group.

In the embodiment of test strip 32, the second channel 72 includes ablank portion 300. The blank portion 300 does not include any reagentgroups and is positioned between the reagent portion 100 and the reagentportion 110 within the second channel 72.

FIG. 2 is a block diagram of a system 10 to calibrate measurements ofone or more test analytes 47 (FIG. 1) from a test sample 40. Thedescription of FIG. 2 is based on the test strip 32 described withreference to FIG. 1 although the description is relevant to otherimplementations of test strips. The system 10 comprises a photodetectorarray 200, a processor 220, a memory 230, at least one light source 250.The system 10 operates on the test strip 32, which receives samples fromthe sample tray 27. The system 10 also includes software 225, which isexecuted by the processor 220 to perform the operations described inthis document. The software 225 is stored or otherwise embodied in or ona storage medium 226. In one implementation of this embodiment, thesystem 10 includes a test strip such as test strip 32. In anotherimplementation of this embodiment, the system 10 includes a test stripand a sample tray, such as the test strip 32 and the sample tray 27.

As shown in FIG. 1, the first channel 70, also referred to here as“test-sample channel 70,” receives the test sample 40. The test sample40 includes either an unknown amount of at least one test analyte 47 oran undetectable amount of the test analyte 47, which is shown flowing inthe first channel 70 over the reagent portions 110 and 100. If anundetectable amount of test analyte 47 is in the test sample 40,photodetectors in the calibration system do not sense any illuminationfrom a reagent portion 100 in the test-sample channel 70 responsive to abonding of the test analyte 47 and the reagent group in the reagentportion 100 during the calibration process. The calibration process isdescribed below with reference to method 1000 of FIG. 10.

A photodetector in a photodetector array or a group of pixels in aphotodetector array are both referred to here as a photodetectorelement. In one implementation of this embodiment, the calibrationsystem does not sense any illumination generated responsive to a bondingevent at a from a reagent portion 100 in the test-sample channel 70,since the generated illumination from the bonding event is at or belowthe noise floor of the photodetector element. In another implementationof this embodiment, the photodetector element in the calibration systemdoes not sense any illumination from a reagent portion 100 in thetest-sample channel 70 because there is no test analyte in the testsample 40 and therefore no bonding event occurred.

The second channel 72, also referred to here as a “first control channel72,” receives a first control sample 42 that is delivered from a well 56of the sample tray 27. The first control sample 42 comprises controlanalytes, which are shown in the second channel 72 flowing over thereagent portions 110 and 100 and over the blank portion 300. The controlanalyte, shown as an “X” and represented generally by 45, is a knownamount of a test analyte 45 reactive to reagents in the respectivereagent portion 100. The control analyte 45 is also known as “firstcontrol analyte 45” and the known amount of the reactive test analyte 45is a first known amount of the reactive test analyte 45. The controlanalyte 47, which is shown as triangles in FIG. 1, is a known amount ofthe test analyte 47 reactive to reagents in the reagent portion 110. Thecontrol analyte 47 is also known as “second control analyte 47” and theknown amount of the reactive test analyte 47 is a first known amount ofthe reactive test analyte 47. Bonding events occur for the first controlanalyte 45 and the reagents in reagent portion 100 in the first controlchannel 72. Bonding events occur for the second control analyte 47 andthe reagents in reagent portion 110 in the first control channel 72.

The third channel 74, also referred to here as “second control channel74,” receives a second control sample 44 that is delivered from a well57 of the sample tray 27, which is shown in the second control channel74 flowing over the reagent portions 110 and 100. The second controlsample 44 also comprises the first control analyte 45 and the secondcontrol analyte 47. The second control sample 44 has a second knownamount of the first test analyte 47 and a second known amount of thesecond test analyte 45. The second known amount is different from thefirst known amount. Bonding events occur for the first control analyte45 and the reagents in reagent portion 100 in the second control channel74. Bonding events occur for the second control analyte 47 and thereagents in reagent portion 110 in the second control channel 74.

In one implementation of this embodiment, more than two control analytesare included in the first control sample 42 and the second controlsample 44. In another implementation of this embodiment, only onecontrol analyte of the first known amount is included in the firstcontrol sample 42 and only one control analyte of the second knownamount is in the second control sample 44.

In yet another implementation of this embodiment, the test stripincludes more than two control channels. In yet another implementationof this embodiment, the test strip includes only one control channel. Inyet another implementation of this embodiment, the test strip includes ablank channel having no reagent groups. In yet another implementation ofthis embodiment, the test strip includes more than one channel with ablank portion 300. Other implementations of embodiments of test stripsare described below with reference to FIGS. 7 and 9.

In yet another implementation of this embodiment, there is more than onereagent portion 100 in the first channel 70, the second channel 72, andthe third channel 74. In yet another implementation of this embodiment,there is more than one reagent portion 100 and more than one reagentportion 110 in the first channel 70, the second channel 72, and thethird channel 74.

The test sample 40 can be a patient sample, a forensic sample, abiological sample or a chemical sample. The test sample 40, the firstcontrol sample 42 and the second control sample 44 are fluid sampleshaving a viscosity to permit wicking in the respective test-samplechannel 70, first control channel 72 and third control channel 74. Inone implementation of this embodiment, the control samples 42 and 44include a base fluid to which the known amounts of one or more controlanalytes are added.

The test sample 40 is wicked into the test-sample channel 70 bycapillary action. The first control sample 42 and the second controlsample 44 are wicked into the first control channel 72 and the secondcontrol channel 74, respectively, by capillary action. The first channel70, the second channel 72 and the third channel 74 can be gel channels,capillary channels, glass channels, paper channels, wettable-fiberchannels. One or more of the first channel 70, the second channel 72 andthe third channel 74 can be a different type of channel than the otherchannels. In one implementation of this embodiment, the reagent portion100 and the reagent portion 110 are inside the capillary channels. Inanother implementation of this embodiment, the reagent portion 100 andthe reagent portion 110 are embedded in the material that forms thecapillary channels. In yet another implementation of this embodiment,the reagent portion 100 and the reagent portion 110 overlay the materialthat forms the capillary channels so that the sample material touchesthe reagent portions 100 and the reagent portions 110 when the sample iswicked through the channels.

As shown in FIG. 1, the test sample 40 and the control samples 42 and 44are delivered to the test strip 32 by a sample tray 27. Other methods ofdelivery of the test sample 40 and the control samples 42 and 44 can beused to allow the test sample 40 and the control samples 42 and 44 towick into the respective channels. In one implementation of thisembodiment, the wells 55, 56 and 57 are not on a single tray orsubstrate. In another implementation of this embodiment, hypodermicneedles deliver the test sample 40 and the control samples 42 and 44 tothe respective first channel 70, the second channel 72 and the thirdchannel 74.

The light source 250 illuminates the test strip 32 with light 260. Aportion of the light 260 that is incident on the test strip 32 isreflected as light 262. A portion of the light 260 that is incident onthe test strip 32 is transmitted through the test strip 32 as light 261.A portion of the light 260 interacts with the reagent portion 100. Theprocessor 220 is communicatively coupled to the photodetector array 200and the memory 230. In one implementation of this embodiment, the memory230 is integral to the photodetector array 200. The system 10 calibratesmeasurements of one or more test analytes 47 in a test sample 40 whilethe photodetector array 200, the light source 250 and the test strip 32,have relative positions in pre-selected locations. The relativepositions include specific distances between the photodetector array200, the light source 250 and the test strip 32. The relative positionsalso include specific angles between the surfaces of the photodetectorarray 200, the light source 250 and the test strip 32.

In one implementation of this embodiment, a portion of the light 260incident on the test strip 32 is transmitted through the test strip 32as light 261 and none of the light 260 is reflected from the test strip32. In another implementation of this embodiment, a portion of the light260 is reflected as light 262 and none of the light 260 is transmittedthrough the test strip 32. In yet another implementation of thisembodiment, at least a portion of the light 260 is absorbed by the teststrip 32.

If a bonding event has occurred at one or more of the reagent portions100 and 110 on the test strip 32, the light 260 stimulates the emissionof a reaction light having a reaction light level from the reagentportion 100 and 110 in which the bonding event occurred. In oneimplementation of this embodiment, if a bonding event has occurred atone or more of the reagent portions 100 and 110 on the test strip 32,the light 260 is reflected as reaction light having a reaction lightlevel from the reagent portion 100 and 110 in which the bonding eventoccurred. The bonding events and the generation of reaction light in thetest strip 32 is described now with reference to FIGS. 3A, 3B, 4A and4B.

FIGS. 3A and 3B are side cross-sectional views of one embodiment of thecontrol channel 72 during a calibration process before and after abonding event, respectively. The plane upon which the cross-sectionviews of FIGS. 3A and 3B are taken is indicated by section line 3-3 inFIG. 1. The reagent group represented generally by 80 in the reagentportion 100 is attached to a surface 35 of the test strip 32 in firstcontrol channel 72. The reagent group 80 is also referred to here as“first reagent group 80.” The reagent group represented generally by 82in the reagent portion 110 is attached to the surface 35 of the teststrip 32 in first control channel 72. The reagent group 82 is alsoreferred to here as “second reagent group 82.” The reagent portion 100is spatially separated from the reagent portion 110 by the blank portion300. There is no reagent group attached to the surface 35 of the teststrip in the blank portion 300. As shown in FIG. 3A, light representedgenerally by 260 is incident on the surface 35 of the test strip 32before a bonding event and no reaction light is emitted from the reagentportion 100 or the reagent portion 110. Any light 260 reflected from thesurface 35 is not shown.

As shown in FIG. 3B, light 260 is incident on the surface 35 of the teststrip 32 after a bonding event so reaction light represented generallyby 150 is emitted from the reagent portion 100 of the first controlchannel 72 and reaction light represented generally by 155 is emittedfrom the reagent portion 110 of the first control channel 72. Thecontrol analyte represented generally by 45, which is a first knownamount of a test analyte 45 that may or may not be in the test sample40, is bonded to the first reagent group 80.

When subjected to the light 260, the control analyte 45 bonded to thereagent group 80 is stimulated to emit reaction light 150. In oneimplementation of this embodiment, light 260 is reflected from thecontrol analyte 45 bonded to the reagent group 80. A photodetectorelement of the photodetector array 200 detects the reaction light 150and the processor 220 that is communicatively coupled to thephotodetector array 200 determines a first reaction light levelcorrelated to the reaction light 150 detected from the reagent portion100 in the first control channel 72.

Based on the location of the photodetector element of the photodetectorarray 200 that detects the reaction light 150, the processor 220 is ableto determine that the reaction light 150 originated at the reagentportion 100 in the first control channel 72. The determination is madebecause the system 10 calibrates measurements of one or more testanalytes 47 in a test sample 40 when the photodetector array 200, thelight source 250 and the test strip 32 have relative positions inpre-selected locations. Based on the pre-selected relative positions andthe angle subtended by the emitted light, the light emitted from knownlocations on the test strip 32 is correlated to known locations on thephotodetector array 220. These correlated positions are stored in thememory 230, which is communicatively coupled to the processor 220. Theprocessor 220 retrieves the information as needed from memory 230 todetermine that the reaction light 150 originated at the reagent portion100 in the first control channel 72.

Likewise, when subjected to the light 260, the control analyte 47 bondedto the reagent group 82 is stimulated to emit reaction light 155. In oneimplementation of this embodiment, light 260 is reflected from thecontrol analyte 47 bonded to the reagent group 82. A photodetectorelement of the photodetector array 200 detects the reaction light 155and the processor 220 determines a first reaction light level correlatedto the reaction light 155 detected from the reagent portion 110 in thesecond control channel 74.

Based on the location of the photodetector element of the photodetectorarray 200 that detects the reaction light 155, the processor 220 is ableto determine that reaction light 155 originated at the reagent portion110 in the first control channel 72 using the correlated positionsstored in the memory 230.

When subjected to the light 260, the blank portion 300 reflects aportion of the light 260 as reference light represented generally by 180into the photodetector array 200. Reference light 180 also includesambient light (not shown) that reflects from the surface 35. There canbe other sources of reference light 180. The photodetector array 200detects the reference light 180 and the processor 220 determines areference-light level correlated to the reference light 180 detectedfrom the blank portion 300 in the first control channel 72. Based on thelocation of the photodetector element of the photodetector array 200that detects the light, the processor 220 is able to determine by thatthe reference light 180 originated at the blank portion 300 in the firstcontrol channel 72 using the correlated positions stored in the memory230.

FIGS. 4A and 4B are side cross-sectional views of one embodiment of atest-sample channel 70 during a calibration process before and after abonding event, respectively. The plane upon which the cross-section viewof FIGS. 4A and 4B are taken is indicated by section line 4-4 in FIG. 1.The reagent group 80 in the reagent portion 100 is attached to thesurface 35 of the test strip 32 in the test-sample channel 70. Thereagent group 82 in the reagent portion 110 is attached to a surface 35of the test strip 32 in the test-sample channel 70. The reagent portion110 is spatially separated from the reagent portion 110 by a region inwhich there is no reagent group attached to the surface 35 of the teststrip 32. In one implementation of this embodiment, the reagent portion100 is adjacent to the reagent portion 110. As shown in FIG. 4A, light260 is incident on the surface 35 of the test strip 32 before a bondingevent so no reaction light is emitted from the reagent portion 100 orthe reagent portion 110. Any light 260 reflected from the surface 35 isnot shown.

As shown in FIG. 4B, light 260 is incident on the surface 35 of the teststrip 32 after a bonding event, so test light represented generally by160 is emitted from the reagent portion 110 of the test-sample channel70.

The test analyte 47, from the test sample 40 having an unknown amount ofa test analyte 45, is bonded to the reagent group 82. When subjected tothe light 260, the test analyte 47 bonded to the reagent group 82 isstimulated to emit test light 160. A photodetector element of thephotodetector array 200 detects the test light 160 and the processor 220determines a test-light level correlated to the test light 160 emittedfrom the reagent portion 110 in the test-sample channel 70. Theprocessor 220 is able to determine by the location of the photodetectorelement of the photodetector array 200 that detects the test light 160,that the test light 160 originated at the reagent portion 110 in thetest-sample channel 70.

However, since the exemplary test sample 40 (as shown in FIG. 1) doesnot include any test analyte 45, there is no bonding of test analytes tothe reagent portion 100 in the test-sample channel 70. When test-samplechannel 70 is subjected to the light 260, the reagent group 80 is notstimulated to emit (or reflect) any light. A photodetector element ofthe photodetector array 200 detects only ambient light but no light dueto a bonding event at the reagent portion 100 in the test-sample channel70. The processor 220 is able to determine by the location of thephotodetector element of the photodetector array 200 that detects theambient light (or light 260 reflected from the reagent portion 100).Based on the determined position, the processor 220 is able to determinethat only ambient light (or light 260 reflected from the reagent portion100) originated at the reagent portion 100 in the test-sample channel70.

The photodetector array 200 detects light correlated to at least tworeagent portions 100 and 110 of the test strip 32. The photodetectorarray 200 detects a reference light from at least one blank portion 300of the test strip 32.

The photodetector array 200 is a photodetector, a one-dimensionalphotodetector array, a two-dimensional photodetector array, acharge-coupled device camera, an array of complimentarymetal-oxide-semiconductor image sensors, or combinations thereof.

FIG. 5 is a block diagram of one embodiment of a system 11 to calibratemeasurements of one or more test analytes 45 from a test sample 40. Thesystem 10 differs from the system 10 of FIG. 2, in that a lens system210 is included in system 10 and a processor 221 is included in thephotodetector array 200. The system 11 also includes a display 234 and areader 232 which are used to display calibration curves or display intext format the amount of one or more test analytes 45. In oneimplementation of this embodiment, the system 11 includes a test stripsuch as test strip 32. In another implementation of this embodiment, thesystem 11 includes a test strip and a sample tray, such as test strip 32and the sample tray 27. In one implementation of this embodiment, allthe described functions of processor 220 are performed by the processor221 in the photodetector array 200. In another implementation of thisembodiment, the described functions of processor 220 are shared by theprocessor 220 and the processor 221 in the photodetector array 200.

In FIG. 5, the test strip 32, the lens system 210 and the photodetectorarray 200 are shown in a side cross-sectional view. The sidecross-sectional view of the test strip 32 is similar to the sidecross-sectional view of FIG. 3B. In FIG. 5, the reagent groups 80 and 82are not shown. The photodetector array 200 and the operation of system11 are discussed with reference to FIG. 5 and FIG. 6.

FIG. 6 is a block diagram of one embodiment of a photodetector array200. The photodetector elements 201, 202 and 203 on or at the surface212 of the photodetector array 200 as shown in the side cross-sectionalview of FIG. 5. The photodetector elements 201-209 of the photodetectorarray 200 are shown arranged on the surface 212 in a rectangular array.

The column 174 of the photodetector array 200 includes photodetectorelements 207, 208 and 209. Test light from the reagent portion 100 (FIG.2) in the test-sample channel 70 is focused by the lens system 210 ontothe photodetector element 207. Test light from the reagent portion 110(FIG. 2) in the test-sample channel 70 is focused by the lens system 210onto the photodetector element 209. In one implementation of thisembodiment, the photodetector element 208 is not in the photodetectorarray 200.

The column 172 of the photodetector array 200 includes photodetectorelements 201, 202 and 203. Reaction light 150 from the reagent portion100 in the second channel 72 is focused by the lens system 210 onto thephotodetector element 201. Reference light 180 from the blank portion300 in the second channel 72 is focused by the lens system 210 onto thephotodetector element 202. Reaction light 155 from the reagent portion100 in the second channel 72 is focused by the lens system 210 onto thephotodetector element 203. As shown in FIG. 5, a portion of the light260 from the light source 250 is transmitted through the test strip 32.Light 260 incident on the photodetector array 200 is detected at thephotodetector element 208 (FIG. 6) and the light intensity is normalizedfor the intensity of the light transmitted through the blank portion 300of the test strip 32.

The column 171 of the photodetector array 200 includes photodetectorelements 204, 205 and 206. Reaction light represented generally by 170from the reagent portion 100 (FIG. 2) in the third channel 74 is focusedby the lens system 210 onto the photodetector element 204. Reactionlight represented generally by 175 from the reagent portion 110 (FIG. 2)in the third channel 74 is focused by the lens system 210 onto thephotodetector element 206. In one implementation of this embodiment, thephotodetector element 205 is not in the photodetector array 200.

These correlated positions, such as the correlation between reagentportion 100 and the photodetector element 201 shown in FIG. 5, arestored in the memory 230, which is communicatively coupled to theprocessor 220. The processor 220 retrieves the information as neededfrom memory 230 to determine that the reaction light 150 originated atthe reagent portion 100 in the first control channel 72.

In one implementation of this embodiment, the photodetector elements201-209 are single photodetectors positioned in an array on the surface212. In another implementation of this embodiment, the photodetectorelements 201-209 are each a group of pixels in a photodetector array220. In yet another implementation of this embodiment, the photodetectorelements 201-209 are each a pixel in a photodetector array 220.

In yet another implementation of this embodiment, each sensor element isa complementary metal-oxide-semiconductor (CMOS) sensor element. Eachsensor element may alternatively be a charge-coupled device (CCD) sensorelement or another suitable type of sensor element that generates anelectrical signal in response to incident light. In one implementationof this embodiment, the lens system 210 is an array of diffractiveoptical elements etched or molded in a plastic substrate. In anotherimplementation of this embodiment, the lens system 210 is an array oflenses positioned in securing framework. There are other ways to formthe lens system 210. The lenses in the lens system 210 are designedbased on the specific distances between the photodetector array 200, thelight source 250 and the test strip 32, the wavelengths of the lightbeing focused and the specific angles between the surfaces of thephotodetector array 200, the light source 250 and the test strip 32. Inanother implementation of this embodiment, the lens system 210 is coatedwith a coating to prevent the transmission of the wavelength orwavelengths of the light 260.

FIG. 7 is a block diagram of one embodiment of a test strip 30. Teststrip 30 is used to calibrate measurements of one analyte in a testsample 40. The test strip 32 can be used in conjunction with acalibration system 10 or 11 as described above below with reference toFIGS. 2 and 5, respectively. The test sample 40 is delivered from a well55 of the sample tray 25 to a first channel 70 of the test strip 30. Thetest sample 40 includes a test analyte as described above with referenceto FIGS. 1 and 2.

The test strip 30 comprises two channels: the first channel 50, a secondchannel 52. Each of the first channel 50 and the second channel 52comprise a reagent portion 100. The reagent portion 100 includes onetype of reagent group. In the embodiment of test strip 30, the secondchannel 52 includes a blank portion 300. The blank portion 300 does notinclude any reagent groups.

FIG. 8 is a flow diagram of one embodiment of a method 800 to determinea presence of a reactive test analyte 45 in a test sample 40. Theparticular embodiment of method 800 shown in FIG. 8 is described here asbeing implemented using the test strip 30 in the system 11 describedabove with reference to FIG. 5. Specifically method 800 is implementedusing the test-sample channel 70 and one control channel 72. In oneimplementation of this embodiment, the software 225 is executed by theprocessor 220 to perform the operations described with reference tomethod 800. In another implementation of this embodiment, the software225 is executed by the processor 221 in the photodetector array 200 toperform the operations described with reference to method 800.

At block 802, a test sample 40 including an unknown amount of the testanalyte 45 is introduced into the test-sample channel 70. The testsample 40 is wicked into the test-sample channel 70 from the well 55 ofthe sample tray 27. At block 804, the control sample 42 including atleast one control analyte 45 and/or control analyte 47 into the controlchannel 72. The control sample 42 is wicked into the control channel 72from the well 56 of the sample tray 27.

At block 806, processor 220 measures at least one test-light levelresponsive to reactions of at least one reagent group 80 and/or reagentgroup 82 (FIG. 4B) and at least one reactive test analyte 47 (FIG. 4B)in the test sample 40. The test light 160 is incident on a photodetectorelement 209 (FIG. 6) in the photodetector array 200. The photodetectorelement 209 generates a signal responsive to the incident test light160. The signal is input to processor 220. The processor 220 generates atest-light level that is correlated to the signal received from thephotodetector element 209. In this manner the processor 220 measures atest-light level responsive to reactions of at least one reagent group82 (FIG. 4B) and at least one reactive test analyte 47 (FIG. 4B) in thetest sample 40.

At block 808, processor 220 measures at least one control-light levelresponsive to reactions of at least one reagent group 80 and/or reagentgroup 82 (FIG. 4B) and at least one control analyte 47 and/or 47 (FIG.3B) in the control sample 42. Each control analyte is a known amount ofat least one reactive test analyte as described above with reference toFIGS. 2, 3A, 3B, 4A and 4B.

The reaction light 150 is incident on the photodetector element 201(FIG. 5) in the photodetector array 200. The photodetector element 201generates a signal responsive to the reaction light 150. The signal isinput to processor 220. The processor 220 generates a control-lightlevel that is correlated to the signal received from the photodetectorelement 201. In one implementation of this embodiment, thereference-light level is measured by the processor 220 in a mannersimilar to the manner in which the control-light level is measured.

At block 810, the processor 220 determines a presence of the reactivetest analyte 47 in the test sample 40 based on the measured test-lightlevels and control-light levels. If the test-light level is below thecontrol-light level, then the amount of the test analyte is less thanthe amount of test analyte in the control sample. If the test-lightlevel is above the control-light level, then the amount of the testanalyte is greater than the amount of test analyte in the controlsample. If the test-light level is above the reference-light level, thenthe test analyte is present in the test sample. Likewise, if thetest-light level is at or below the reference-light level, then the testanalyte is not present in the test sample.

The wavelength of the lights 260, 150, 155, 180, 160, 170 and 175described here are dependent upon the reagent groups and the analytes.For all the implementations described herein, the wavelength of thelight 260 is suited to cause an attached reagent group and the reactivetest analyte to emit light of a known wavelength. In one implementationof this embodiment, the light source 250 emits light 260 having morethan one wavelength from different spectral regions. In anotherimplementation of this embodiment, the light source 250 emits light 260having wavelengths over a continuous range of wavelengths.

The photodetector elements 201-209 are suited to detect the wavelengthsof the emitted test light 160 and control light 150, 155, 170 and 175and reference light 180. In one implementation of this embodiment, thephotodetector elements 201-209 detect different ranges of wavelengths.The systems 10 and 11 are designed for various test analytes reactingwith specific reagents that emit light or reflect light of a knownwavelength based on the wavelength of the light 260 emitted from thelight source 250.

FIG. 9 is a block diagram of one embodiment of a test strip 31. The teststrip 31 is used to calibrate measurements of one or more test analytesin a test sample 40. The test strip 31 is used in conjunction with acalibration system 10 or 11 as described below with reference to FIGS. 2and 5, respectively.

The test strip 31 comprises four channels: the first channel 60, asecond channel 62, a third channel 64 and a fourth channel 66. Each ofthe first channel 60, the second channel 62, and the third channel 64comprise reagent portions 100 and reagent portions 110. The fourthchannel 66 does not include any reagent portions and as such isequivalent to the blank portion 300 in the test strip 32.

The first channel 60, also referred to here as “test-sample channel 60,”receives the test sample 40 as described above with reference to FIG. 1.The second channel 62, also referred to here as a “first control channel62,” receives a first control sample 42 that is delivered from a well 56of the sample tray 26. The third channel 64, also referred to here as“second control channel 64,” receives a second control sample 44 that isdelivered from a well 57 of the sample tray 26. The fourth channel 66,also referred to here as “blank channel 66,” receives the second controlsample 44 that is delivered from a well 58 of the sample tray 26.

FIG. 10 is a flow diagram of one embodiment of a method 1000 todetermine an amount of a reactive test analyte 45 in a test sample 40.The particular embodiment of method 1000 shown in FIG. 10 is describedhere as being implemented using either system 10 or 11 described abovewith reference to FIGS. 2 and 5, respectively, operating on the teststrip 31 described above with reference to FIG. 9. The exemplary teststrip 31 is similar to the exemplary test strip 32 in that the reagentportions 100 and 110 react to control analytes 45 and 47, respectively.The blank portion 300 of test strip 32 is equivalent to the blankchannel 66 of test strip 31.

Method 1000 is implemented for a system having at least two controlchannels. The software 225 is executed by the processor 220 to performthe operations described with reference to method 1000.

Method 1000 is implemented with portions of method 800. Method 1000begins after block 802 of method 800 is implemented for the test strip31, so that the test sample 40 including an unknown amount of the testanalyte 45 has been introduced into the test-sample channel 60 from thewell 55 of the sample tray 26 prior to step 1002. In one implementationof this embodiment, the process at blocks 802 and 1002 occur at the sametime.

At block 1002, the first control sample 42 including the first knownamount of control analyte 47 is introduced into the first controlchannel 62. In one implementation of this embodiment, the first controlsample 42 also includes a first known amount of control analyte 45 soboth the control analyte 45 and 47 are introduced into the first controlchannel 62.

At block 1004, the second control sample 44 including the second controlanalyte 47 having a second known amount of the first test analyte 47 isintroduced into the second control channel 64. In one implementation ofthis embodiment, the second control sample 44 also includes a secondknown amount of control analyte 45 so both the control analyte 45 and 47are introduced into the second control channel 64.

At block 1006, the second control sample 44 including the second controlanalyte 47 having a second known amount of the first test analyte 47 isintroduced into the blank channel 66. In one implementation of thisembodiment, the first control sample 42 including the first controlanalyte 47 having a first known amount of the first test analyte 47 isintroduced into the blank channel 66.

Before block 1008 is implemented, blocks 806 and 808 in the method 800of FIG. 8 are implemented and the processor 220 determines reactionlight levels correlated to the light detected from each of the reagentportions 100 and 110. The processor 220 also determines thereference-light levels correlated to the blank channel 66 (or blankportion 300 of test strip 32).

The processor 220 measures at least one first control-light levelresponsive to reactions of at least one first reagent group 80 and/orsecond reagent group 82 (FIG. 4B) and at least one control analyte 45and/or 47 (FIG. 3B) in the control sample 42 after it flows through thefirst control channel 62. As described above, the first control light isemitted from the test strip 31 after light 260 is incident on the teststrip 31 and the processor 220 determines a first reaction light levelfor the first control light.

The processor 220 also measures at least one second control-light levelresponsive to reactions of at least one first reagent group 80 and/orsecond reagent group 82 and at least one control analyte 45 and/or 47 inthe control sample 44 after it flows through the second control channel64. As described above, the second control light is emitted from thetest strip 31 after light 260 is incident on the test strip 31 and theprocessor 220 determines the second reaction light level for the secondcontrol light.

The processor 220 also measures at least one test-light level responsiveto reactions of at least one reagent group 80 and/or reagent group 82and at least one reactive test analyte 45 and/or 47 in the test sample40. As described above, the test light is emitted from the test strip 31after light 260 is incident on the test strip 31 and the processor 220determines a third reaction light level (also referred to here astest-light level) for the test light.

The processor 220 also determines at least one reference-light levelresponsive to at least one control analyte 45 and/or 47 in the controlsample 44 flowing through the blank channel 66. The control sample 44may have absorptive or reflective qualities that modify the controllight emitted (or reflected) from the test strip 31. The reference lightfrom the blank channel 66 (or from the blank portion 300) is dependentupon such absorptive or reflective qualities of the control sample. Thereference light from the blank channel 66 is independent upon thequalities of the reaction between any analytes and reagents.

In one implementation of this embodiment, the processor 220 adjusts eachreaction light level by the reference-light level. The processor 220subtracts the reference-light level from the reaction light levels foreach reagent group to form adjusted reaction light levels. The processor220 subtracts the reference-light level from the test-light levels toform adjusted test-light levels. The processor 220 subtracts thereference-light level from the control-light levels to form adjustedcontrol-light levels.

At block 1008, the processor 220 forms calibration curves for each ofthe reagent groups based on the control-light levels from spatiallyseparate reactions of each of the reagent groups and at least twocontrol analytes having two known amounts of the test analyte.

The processor 220 uses the adjusted control-light level for the reagentportion 100 in the first control channel 62 and the first known level ofthe control analyte 45 as the first point of the calibration curve forthe test analyte 45. The processor 220 uses the adjusted control-lightlevel for the reagent portion 100 in the second control channel 64 andthe second known level of the control analyte 45 as the second point ofthe calibration curve for the test analyte 45.

The processor 220 uses the adjusted control-light level for the reagentportion 110 in the first control channel 62 and the first known level ofthe control analyte 47 as the first point of the calibration curve forthe test analyte 47. The processor 220 uses the adjusted control-lightlevel for the reagent portion 110 in the second control channel 64 andthe second known level of the control analyte 47 as the second point ofthe calibration curve for the test analyte 47.

In an embodiment in which the test strip does not include a blankportion or a blank channel, the processor 220 operates on the unadjustedlight levels. In such a case, the processor 220 uses the control-lightlevel for the reagent portion 100 in the first control channel 62 andthe first known level of the control analyte 45 as the first point ofthe calibration curve for the test analyte 45. The processor 220 usesthe control-light level for the reagent portion 100 in the secondcontrol channel 64 and the second known level of the control analyte 45as the second point of the calibration curve for the test analyte 45.

The processor 220 uses the control-light level for the reagent portion110 in the first control channel 62 and the first known level of thecontrol analyte 47 as the first point of the calibration curve for thetest analyte 47. The processor 220 uses the control-light level for thereagent portion 110 in the second control channel 64 and the secondknown level of the control analyte 47 as the second point of thecalibration curve for the test analyte 47.

In one implementation of this embodiment, there are more than two pointsfor every calibration curve. In this case, there is an additionalcontrol channel in the test strip for each additional point on thecalibration curve.

In another implementation of this embodiment, there are more than twocalibration curves. For each additional calibration curve there is anadditional reagent portion for a different reagent group in thetest-sample channel and in each of the control channels.

At block 1010, the processor 220 determines an amount of the testanalytes 47 in the test sample 40 from a placement of the test-lightlevel for each test analyte 47 on the respective calibration curve forthe control analytes 47.

The processor 200 determines if test light is detected for a testanalyte 47, determines the test-light level for the detected test lightand adjusts the test-light level by the reference-light level. Then theprocessor 200 determines where the adjusted light level is situated inthe calibration curve for the test analyte.

Consider an exemplary case in which the test analyte 45 is reactive withthe reagent group in the reagent portion 100 and the adjusted test-lightlevel from the reagent portion 100 in the test-sample channel 60 ismidway between two adjusted control-light levels in the calibrationcurve for the test analyte 45. In this case, the adjusted test-lightlevel from the reagent portion 100 in the test-sample channel 60 isequal to (CLL2−CLL1)/2+CLL1, where CLL1 is the adjusted lowercontrol-light level from the reagent portion 100 and CLL2 is theadjusted higher control-light level from the reagent portion 100. Thenthe amount of the test analyte 45 equals (KA2−KA1)/2+KA1, where KA1 isthe first known amount of test analyte 45 in the first control channel62 and KA2 is the second higher known amount of test analyte 45 in thesecond control channel 64.

To extend the exemplary case, the test analyte 47 is reactive with thereagent group in the reagent portion 110. The adjusted test-light levelfrom the reagent portion 110 in the test-sample channel 60 is betweenthe two adjusted control-light levels in the calibration curve for thetest analyte 47. The two adjusted control-light levels have a differenceΔCLL. The adjusted test-light level from the reagent portion 110 has avalue that is a quarter of the difference ΔCLL above the lower adjustedcontrol-light level. In this case, the adjusted test-light level fromthe reagent portion 110 in the test-sample channel 60 is equal to(CLL4−CLL3)/4+CLL3, where CLL3 is the adjusted lower control-light levelfor the light from the reagent portion 110, CLL4 is the adjusted highercontrol-light level from the reagent portion 110 and ΔCLL=CLL4−CLL3.Then the amount of the test analyte 47 equals (KA4−KA3)/2+KA3, where KA3is the first known amount of test analyte 47 in the first controlchannel 62 and KA4 is the higher second known amount of test analyte 47in the second control channel 64.

In this manner, the processor 220 determines reaction light levelscorrelated to the light detected from each of the reagent portions,determines a reference-light level correlated to the blank portion 300or blank channel 66, forms calibration curves for respective reagentgroups based on respective first reaction light levels and respectivesecond reaction light levels and determines an amount of one or moretest analytes 47 in the test sample 40 based on placements of thirdreaction light levels on respective calibration curves.

In one implementation of this embodiment, the processor 220 adjusts eachreaction light level by the reference-light level, forms calibrationcurves for respective reagent groups based on respective first adjustedreaction light levels and respective second adjusted reaction lightlevels and determines an amount of one or more test analytes in the testsample based on placements of third adjusted reaction light levels onrespective calibration curves.

FIG. 11 a cross-sectional side view of one embodiment of a system 9 tocalibrate measurements of one or more test analytes from a test sample.FIGS. 12A-12C are cross-sectional front views of one embodiment of thesystem 9 to calibrate measurements of one or more test analytes from atest sample at different times during a calibration process. In thisimplementation of system 9, the test strip 32 is scanned through thesystem 9 after being exposed to the test sample 40, control sample 42and control sample 44.

As shown in FIG. 11, the test strip 32 moves through the reader system400 in the direction of the arrow 5. The reader system 400 includes thelight source 250, a 3×1 linear array of lenses 211, a one-dimensionalphotodetector array 310, processor 220, memory 230 and display 234. Theone-dimensional photodetector array 310 comprises photodetector elements306, 301 and 304 positioned in a 3×1 linear array.

The light 260 from the light source 250 shines on a single row 105 or106 of the reagent portions 100 or 110, respectively, (FIG. 1) of thetest strip 32. At the moment of scanning shown in FIG. 12A, the light260 is incident on the reagent portions 100 in the row 105 of the teststrip 32 (FIG. 1). Reaction light 150 emitted from the reagent portion100 of the first control channel 72 (FIG. 2) is focused by the lineararray of lenses 211 onto the photodetector element 301 while reactionlight 170 from the reagent portion 100 in the second control channel 74(FIG. 2) is focused by the lens system 210 onto the photodetectorelement 304. The processor 220 is communicatively coupled to theone-dimensional photodetector array 310 and operates as described aboveto form a calibration curve 410 and to determine a presence and/oramount of a test analyte in the test sample 40. The calibration curve410 is shown in the display 234 as a function of intensity (INT) andamount of test analyte. Exemplary text “0 TEST ANALYTE” indicates thatthere was no test analyte 45 (FIG. 4B) in the test sample 40.

The test strip 32 moves further through the reader system 400 so that,as shown in FIG. 12B, the light 260 is incident on the blank portion 300in the test strip 32 (FIG. 1). The blank portion 300 transmits a portionof the light 260 as reference light 180 into the photodetector array200. The reference light 180 and the processor 220 is focused by thelinear array of lenses 211 onto the photodetector element 301 Theprocessor 220 operates as described above to determine a reference-lightlevel correlated to the reference light 180 detected from the blankportion 300 in the first control channel 72. The reference-light levelis shown in the display 234 as a circle.

The test strip 32 moves further through the reader system 400 so that,as shown in FIG. 12C, the light 260 is incident on the reagent portions110 in the row 106 of the test strip 32 (FIG. 1). As described abovewith reference to FIG. 2, reaction light 160 emitted from the reagentportion 110 of the test-sample channel 70. Reaction light 160 is focusedby the linear array of lenses 211 onto the photodetector element 306.Reaction light 155 is emitted from the reagent portion 110 of the firstcontrol channel 72 and is focused by the linear array of lenses 211 ontothe photodetector element 301. Reaction light 175 is emitted from thereagent portion 110 (FIG. 2) in the second control channel 74 is focusedby the linear array of lenses 211 onto the photodetector element 304.The processor 220 is communicatively coupled to the one-dimensionalphotodetector array 310 and operates as described above to form acalibration curve 412 and to determine a presence and/or amount of atest analyte in the test sample 40. The calibration curve 412 is shownin the display 234. The test-light level is indicated as an asterisk (*)on the calibration curve 412 and the text “Z TEST ANALYTE” indicatesthat there was test analyte 47 in a amount “Z” in the test sample 40.

Other methods of scanning a test strip 32 across a one-dimensionalphotodetector array 310 are possible. In one implementation of thisembodiment, the test strip 32 is manually scanned across aone-dimensional photodetector array 310. In another implementation ofthis embodiment, the test strip 32 is inserted into a slot in a readersystem and is ejected from the same slot after all the reagent portions100 and blank portions 300 of the test strip have been scanned by thelight 260 and the reaction light was subsequently detected at theone-dimensional photodetector array 310 for each row 105 and 106 ofreagent portions 100 and 110, respectively.

The methods and techniques described here may be implemented in digitalelectronic circuitry, or with a programmable processor (for example, aspecial-purpose processor or a general-purpose processor such as acomputer) firmware, software, or in combinations of them. Apparatusembodying these techniques may include appropriate input and outputdevices, a programmable processor, and a storage medium tangiblyembodying program instructions for execution by the programmableprocessor. A process embodying these techniques may be performed by aprogrammable processor executing a program of instructions to performdesired functions by operating on input data and generating appropriateoutput. The techniques may advantageously be implemented in one or moreprograms that are executable on a programmable system including at leastone programmable processor coupled to receive data and instructionsfrom, and to transmit data and instructions to, a data storage system,at least one input device, and at least one output device. Generally, aprocessor will receive instructions and data from a read-only memoryand/or a random access memory.

Storage devices suitable for tangibly embodying computer programinstructions and data include all forms of non-volatile memory,including by way of example semiconductor memory devices, such as EPROM,EEPROM, and flash memory devices; magnetic disks such as internal harddisks and removable disks; magneto-optical disks; and DVD disks. Any ofthe foregoing may be supplemented by, or incorporated in,specially-designed application-specific integrated circuits (ASICs).

A number of embodiments of the invention defined by the following claimshave been described. Nevertheless, it will be understood that variousmodifications to the described embodiments may be made without departingfrom the spirit and scope of the claimed invention. Accordingly, otherembodiments are within the scope of the following claims.

What is claimed is:
 1. A system adapted to calibrate measurements of oneor more test analytes in a test sample, the system comprising: a teststrip comprising: a first channel configured to receive a test samplecomprising an unknown amount of a first test analyte, the first channelcomprising a first type of reagent group configured to bind with andgenerate reaction light when bound to the first test analyte, whenpresent in the test sample, the first channel further comprising asecond type of reagent group downstream of and different than the firsttype of reagent group, the second type of reagent group configured tobind with and generate reaction light when bound to a second testanalyte different than the first test analyte; and a second channelconfigured to receive a control sample comprising a known amount of thefirst test analyte and a known amount of the second test analyte, thesecond channel comprising the first type of reagent group configured tobind with and generate reaction light when bound to the first testanalyte in the control sample, the second channel further comprising thesecond type of reagent group downstream of and different than the firsttype of reagent group, the second type of reagent group configured tobind with and generate reaction light when bound to the second testanalyte in the control sample, wherein the second channel comprises ablank portion having no reagent group, the blank portion positionedbetween the first type of reagent group and the second type of reagentgroup, wherein the first channel and the second channel are spatiallyseparated from each other by a region in which there is no reagent groupattached to a surface of the test strip to prevent liquid contact, andwherein the first type of reagent group in the first channel and thefirst type of reagent group in the second channel form a row that isperpendicular to the first channel and the second channel; and aprocessor configured to: determine light levels correlated to reactionlight generated by the reagent groups in the first channel and thesecond channel, respectively; and determine a presence of the first testanalyte in the test sample when the light level correlated to thereaction light generated by the first type of reagent group in the firstchannel is above the light level correlated to the reaction lightgenerated by the first type of reagent group in the second channel. 2.The system of claim 1, wherein the test strip further comprises: a blankchannel having no reagent groups.
 3. The system of claim 1, in which thechannels of the test strip are selected from the group consisting of agel channel, a capillary channel, a glass channel, a paper channel, awettable-fiber channel and combinations thereof.
 4. A device adapted tocalibrate measurements of one or more test analytes in a test sample,the device comprising: a sample tray having a first well configured tohold the test sample and a second well configured to hold a firstcontrol sample, the test sample comprising an unknown amount of a firsttest analyte, the first control sample comprising a known amount of thefirst test analyte and a known amount of a second test analyte differentthan the first test analyte; a test strip comprising: a first channelcomprising a first type of reagent group configured to bind with andgenerate first test light when bound to the first test analyte, whenpresent in the test sample, the first channel further comprising asecond type of reagent group downstream of and different than the firsttype of reagent group, the second type of reagent group configured tobind with and generate second test light when bound to the second testanalyte, the first channel positioned to wick the test sample from thefirst well; and a second channel comprising the first type of reagentgroup configured to bind with and generate first control light whenbound to the first test analyte in the first control sample, the secondchannel further comprising the second type of reagent group downstreamof and different than the first type of reagent group, the second typeof reagent group configured to bind with and generate second controllight when bound to the second test analyte in the first control sample,wherein the second channel comprises a blank portion having no reagentgroup, the blank portion positioned between the first type of reagentgroup and the second type of reagent group, the second channelpositioned to wick the first control sample from the second well,wherein the first channel and the second channel are spatially separatedfrom each other by a region in which there is no reagent group attachedto a surface of the test strip to prevent liquid contact, and whereinthe first type of reagent group in the first channel and the first typeof reagent group in the second channel form a row that is perpendicularto the first channel and the second channel; and a processor configuredto: determine light levels correlated to test light and control lightgenerated by the reagent groups in the first channel and the secondchannel, respectively; and determine a presence of the first testanalyte in the test sample when the light level correlated to the testlight generated by the first type of reagent group in the first channelis above the light level correlated to the first control light generatedby the first type of reagent group in the second channel.
 5. The deviceof claim 4, wherein the test strip further comprises: a blank channelhaving no reagent groups.
 6. The device of claim 4, in which thechannels are selected from the group consisting of a gel channel, acapillary channel, a glass channel, a paper channel, a wettable-fiberchannel and combinations thereof.
 7. The system of claim 1, wherein thesecond type of reagent group in the first channel and the second type ofreagent group in the second channel form a row that is perpendicular tothe first channel and the second channel.
 8. The device of claim 4,wherein the second type of reagent group in the first channel and thesecond type of reagent group in the second channel form a row that isperpendicular to the first channel and the second channel.
 9. The systemof claim 1, further comprising a third channel comprising the first typeof reagent group configured to bind with and generate reaction lightwhen bound to the first test analyte, the third channel furthercomprising the second type of reagent group downstream of and differentthan the first type of reagent group, the second type of reagent groupconfigured to bind with and generate reaction light when bound to thesecond test analyte, wherein the third channel is adapted to receive asecond control sample having a second known amount of the first testanalyte and a second known amount of the second test analyte.
 10. Thedevice of claim 4, further comprising a third channel comprising thefirst type of reagent group configured to bind with and generate a thirdcontrol light when bound to the first test analyte, the third channelfurther comprising the second type of reagent group downstream of anddifferent than the first type of reagent group, the second type ofreagent group configured to bind with and generate fourth control lightwhen bound to the second test analyte, wherein the third channel isadapted to receive a second control sample having a second known amountof the first test analyte and a second known amount of the second testanalyte.
 11. The device of claim 4, wherein the processor is furtherconfigured to determine a reference light level correlated to the blankportion, and wherein the light levels correlated to the test light andthe control light generated by the reagent groups is adjusted by thereference light level.
 12. A device adapted to calibrate measurements ofone or more test analytes in a test sample, the device comprising: atest strip comprising: a first channel configured to receive a testsample comprising an unknown amount of a first test analyte, the firstchannel comprising a first type of reagent group configured to bind withand generate first test light when bound to the first test analyte, whenpresent in the test sample, the first channel further comprising asecond type of reagent group downstream of and different than the firsttype of reagent group, the second type of reagent group configured tobind with and generate second test light when bound to a second testanalyte different than the first test analyte; a second channelconfigured to receive a first control sample comprising a known amountof the first test analyte and a known amount of a second test analyte,the second channel comprising the first type of reagent group configuredto bind with and generate first control light when bound to the firsttest analyte in the first control sample, the second channel furthercomprising the second type of reagent group downstream of and differentthan the first type of reagent group, the second type of reagent groupconfigured to bind with and generate second control light when bound tothe second test analyte in the first control sample, wherein the secondchannel comprises a blank portion having no reagent group, the blankportion positioned between the first type of reagent group and thesecond type of reagent group; and a third channel configured to receivea second control sample comprising a second known amount of the firsttest analyte and a second known amount of the second test analyte, thethird channel comprising the first type of reagent group configured tobind with and generate a third control light when bound to the firsttest analyte, the third channel further comprising the second type ofreagent group downstream of and different than the first type of reagentgroup, the second type of reagent group configured to bind with andgenerate fourth control light when bound to the second test analyte,wherein the first channel and the second channel are spatially separatedfrom each other by a region in which there is no reagent group attachedto a surface of the test strip to prevent liquid contact, and whereinthe first type of reagent group in the first channel and the first typeof reagent group in the second channel form a row that is perpendicularto the first channel and the second channel; and a processor configuredto: determine a test light level correlated to test light generated bythe first type of reagent group in the first channel; determine controllight levels correlated to control light generated by the first type ofreagent groups in the second and third channels; form a calibrationcurve based on the determined control light levels correlated to thefirst type of reagent groups in the second and third channels; anddetermine an amount of the first test analyte in the test sample basedon placement of the determined test light level on the calibrationcurve.
 13. The device of claim 12, wherein the second type of reagentgroup in the first channel, the second type of reagent group in thesecond channel, and the second type of reagent group in the thirdchannel form a row that is perpendicular to the first channel, thesecond channel, and the third channel.
 14. The device of claim 12,wherein the processor is further configured to determine a referencelight level correlated to the blank portion, and wherein the lightlevels correlated to the test light and the control light generated bythe reagent groups is adjusted by the reference light level.